1. Field of the Invention
This invention relates to a process for the production of methacrolein and methacrylic acid by the gas phase catalytic oxidation of isobutylene or t-butanol using molecular oxygen, and more specifically to certain new catalysts used in the process thereof.
2. Description of the Prior Art
Numerous catalysts have been proposed for use in the production of methacrolein and methacrylic acid via the catalytic oxidation of isobutylene or t-butanol in a gas phase at high temperatures. For example, U.S. Pat. Nos. 4,380,664 and 4,111,984 disclose the use of MoSbBiFeNi(Sn)[K, Rb, Cs][Co, U, Ge, W, Ti] catalysts in the gas phase catalytic oxidation of isobutylene and t-butanol, respectively. Similarly, Japanese Patent Publication [Kokai] No. 27709/77 discloses the use of MoSbBiFeCo[alkali metals][Ni, Sn, Cr, Mn, Ti, W, Mg] catalysts in the gas phase catalytic oxidation of isobutylene. However, from an industrial standpoint, improvement still needs to be made in the performance of the catalysts used in this reaction, especially with regard to such properties as catalytic activity, selectivity for methacrolein and methacrylic acid, and life of the catalyst.